On top of that, even iOS 9’s primary focus is improving performance, it appears the new software isn’t necessarily going to make your old iOS device feel any faster than iOS 8.

A series of videos posted by YouTube channel iAppleBytes seems to indicate that the iPhone 4s, iPhone 5 and even iPhone 5s will offer you a slightly slower iOS 9 experience. Booting takes longer, especially on old devices, and there’s some lag across the board.

The videos do show that Siri is ready to offer quicker responses in iOS 9.0.1 rather than iOS 8.4.1. A similar video comparison released last week also showed that while app launching might be slower on older iOS devices, Wi-Fi speed and Internet browsing are improved in iOS 9 across devices.

There are various tricks users can do to improve overall speed in iOS 9, especially on older gadget including the iPhone 4s and iPad 2 – see this post for more details. Additionally, users can choose to downgrade to iOS 8.4.1 for a limited time, as Apple keeps signing both releases – here’s how to do it.

Meanwhile, the three iAppleBytes comparison videos that show performance differences between iOS 9.0.1 and iOS 8.4.1 on the iPhone 4s, iPhone 4 and iPhone 5s follow below.